期刊
TOXICOLOGY AND APPLIED PHARMACOLOGY
卷 272, 期 3, 页码 780-786出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.taap.2013.08.002
关键词
Methoxychlor; Metabolites; Antral follicles; Ovary; Pregnenolone; Steroidogenesis
资金
- National Institute of Environmental Health Sciences (NIEHS) [R01ES019178, K99ES021467]
- University of Illinois Billie A. Field Fellowship in Reproductive Biology program
- Environmental Toxicology Scholarship
Mono-hydroxy methoxychlor (mono-OH MXC) is a metabolite of the pesticide, methoxychlor (MXC). Although MXC is known to decrease antral follicle numbers, and increase follicle death in rodents, not much is known about the ovarian effects of mono-OH MXC. Previous studies indicate that mono-OH MXC inhibits mouse antral follicle growth, increases follicle death, and inhibits steroidogenesis in vitro. Further, previous studies indicate that CYP11A1 expression and production of progesterone (P-4) may be the early targets of mono-OH MXC in the steroidogenic pathway. Thus, this study tested whether supplementing pregnenolone, the precursor of progesterone and the substrate for HSD3B, would prevent decreased steroidogenesis, inhibited follicle growth, and increased follicle atresia in mono-OH MXC-treated follicles. Mouse antral follicles were exposed to vehicle (dimethylsulfoxide), mono-OH MXC (10 mu g/mL), pregnenolone (1 mu g/mL), or mono-OH MXC and pregnenolone together for 96 h. Levels of P-4, androstenedione (A), testosterone (T), estrone (E-1), and 17 beta-estradiol (E-2) in media were determined, and follicles were processed for histological evaluation of atresia. Pregnenolone treatment alone stimulated production of all steroid hormones except E-2. Mono-OH MXC-treated follicles had decreased sex steroids, but when given pregnenolone, produced levels of P-4, A, T, and E-1 that were comparable to those in vehicle-treated follicles. Pregnenolone treatment did not prevent growth inhibition and increased atresia in mono-OH MXC-treated follicles. Collectively, these data support the idea that the most upstream effect of mono-OH MXC on steroidogenesis is by reducing the availability of pregnenolone, and that adding pregnenolone may not be sufficient to prevent inhibited follicle growth and survival. (C) 2013 Elsevier Inc. All rights reserved.
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